Conventionally, when it is desired to actuate a downhole tool, such as a packer, a cutter, a torch, a perforating gun, a setting tool, or a similar type of apparatus, a two-part process must be performed. First, a logging tool must be lowered into a wellbore, to the desired location, and used to record the wellbore temperature and pressure at that location. After the logging tool is retrieved to the surface, this data is used to program the downhole tool and/or an associated actuation tool with predetermined values. Specifically, the downhole tool and/or the actuation tool is programmed with an expected or predetermined pressure or pressure range, and an expected or predetermined temperature or temperature range, and then the downhole tool and/or the actuation tool is/are lowered into the wellbore. When these programmed conditions are detected by the downhole tool and/or the actuation tool, it is assumed that the downhole tool is located at the desired location, and the tool is actuated.
Typically, the tool is lowered into the wellbore with an associated timer to prevent premature actuation of the tool, such as an unexpected increase in temperature or pressure caused by the exodus of gas from the well, which could increase the pressure and temperature to the programmed levels prior to the tool reaching the desired depth. The timer is programmed at the surface of the well with a preset duration, estimated to be the approximate amount of time required for the tool the reach the desired location in the well. After the preset duration expires, the tool becomes “armed,” such that exposure to the programmed temperature and pressure will cause the tool to become actuated. If the tool does not reach the desired location within the preset time interval for any reason, the tool may become actuated at a different location, if the programmed pressure and temperature values are detected elsewhere in the wellbore. Further, if the tool does not become actuated at the desired location for any reason, it must be retrieved to the surface in an armed state, which can potentially cause unintended actuation at an undesired location during retrieval and related damage to the wellbore, or the possibility of an actuation at the surface, which can cause catastrophic damage and/or injury.
Because logging and tool actuation are performed as separate operations, the reasons that a downhole tool fails to actuate at the proper location may be difficult to determine. The ambient temperature and pressure of the wellbore is typically not logged when lowering a downhole tool, primarily due to the size of the components involved. A downhole tool, when engaged with an actuation tool, may have a length of thirty feet or greater. The addition of a logging tool to this lengthy assembly can cause the overall length to become prohibitive.
Additionally, conventional actuation tools are subject to other inherent difficulties, such as poor battery life and/or the use of potentially hazardous batteries (e.g., lithium batteries, which can be subject to restrictions on transport, use, and disposal thereof), and improper grounding. The high temperature environment within a wellbore significantly reduces the life of batteries, such that it becomes necessary to lower and actuate a tool quickly, before the loss of battery power prevents further operation of the tool. To at least slightly extend the battery life of such tools, conventional actuation tools are normally powered using dangerous lithium and/or cadmium batteries, which are subject to burdensome regulations regarding the transport, use, and disposal thereof, primarily due to the possibility of explosion as well as the possibility of negative environmental impact following disposal. Further, one of the primary reasons for the failure to actuate downhole tools is improper grounding thereof, as the proper grounding is often difficult to verify until the tool has successfully been actuated. However, until a tool has been retrieved to the surface, normally in an “armed” state, as described above, the reason a tool has failed to actuate, whether due to improper grounding or another cause, is normally unknown.
A need exists for a logging and actuation tool that overcomes one or more of the above-referenced deficiencies by reducing or eliminating the possibility of actuation at an improper location, providing a more reliable mechanism for grounding the tool, and significantly reducing the size of the overall tool to enable simultaneous logging and actuation runs, while also increasing the possible uses for such a tool, such as by sizing the tool to enable insertion into coiled tubing or similar narrow conduits, such as small diameter pipe (e.g., having a diameter of 2 inches or less) and/or conduits having narrow restrictions.
A need also exists for a combined logging and actuation tool that is safe to operate, easy and inexpensive to transport, and can be powered using non-hazardous power sources, thus reducing the expense associated with transport and/or disposal of materials.